package main

import (
	"io/ioutil"
	"fmt"
)

func grade(score int) string {
	g := ""
	switch {
	case score < 0 || score > 100:
		panic(fmt.Sprintf("Wrong score: %d,", score))
	case score < 60:
		g = "F"
	case score < 80:
		g = "C"
	case score < 90:
		g = "B"
	case score < 100:
		g = "100"
	default:
		panic(fmt.Sprintf("Wrong score: %d,", score))
	}
	return g
}

func main() {
	const fileName = "abc.txt"
	contents, err := ioutil.ReadFile(fileName)
	if err != nil {
		fmt.Println(err)
	} else {
		fmt.Println("%s\n", contents)
	}
}
